# MAL-2026-6326: Malicious code in web3-eth-utils (npm)


- **Type:** Malicious package
- **Package:** `web3-eth-utils` (npm)
- **Published:** 23 Jun 2026
- **Also known as:** GHSA-f5r2-qmg4-83w6

## What is MAL-2026-6326?

MAL-2026-6326 is a malicious package in web3-eth-utils, published on 23 Jun 2026. 

### Official description

Package name, README, repository URL, contributors, and module structure are copied from the legitimate '@ethereumjs/util' / 'ethereumjs-util' package, presenting itself as a drop-in for that widely-used Ethereum utility library. The compiled Node entry dist/index.js contains a side-effect-only `require("assertcore")` at line 60 (no symbols from the module are used), and assertcore is declared as a runtime dependency (^3.1.7) in package.json. This `require` is absent from the TypeScript source src/index.ts and from the browser bundle dist.browser/index.js — it was injected into the shipped Node bundle after the build, a deliberate smuggling pattern. Any consumer who installs web3-eth-utils believing it to be the real ethereumjs util package will pull assertcore into their dependency tree and execute its top-level code at every `require('web3-eth-utils')`, handing arbitrary install/require-time execution to the assertcore maintainer.

Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.

## What should I do about MAL-2026-6326?

Remove the package from your dependencies and lockfiles, then rotate any secrets on machines where it was installed.

## Fix prompt for AI coding agents

```text
MAL-2026-6326 is a malicious package: web3-eth-utils (npm). Every version was published to cause harm.

Task:
1. Search this repository's dependency manifests and lockfiles for the package, including transitive dependencies.
2. If it is present, remove it, regenerate the lockfile with the project's package manager, and replace whatever it was used for.
3. List any CI runners, developer machines or containers that installed it, so their secrets can be rotated.
4. If the package is not used anywhere, say so and change nothing.

Reference: https://insights.sbomify.com/MAL-2026-6326/ (Markdown: https://insights.sbomify.com/MAL-2026-6326/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-6326

---
From sbomify Insights: https://insights.sbomify.com/MAL-2026-6326/
Summaries are generated and may contain mistakes; the official description above is the record.